Carburetor



Sept. 13, 1927.

F. C. MOCK ET AL CARBURETOR Filed Junell 1921 m nw fim by MW Oliw Patented Sept. 13, 1927.

UNITED STATES PATENT OFFICE.

FRANK C. MOCK, CHARLES J. GUSTAFSON, AND MILTON CHANDiIER, OF CHICAGO, ILLINOIS, ASSIGNORS TO STROMBERG MOTOR DEVICES COMPANY, OF CHICAGO,

ILLINOIS, A CORPORATION OF ILLINOIS.

GARBURETOR.

Application filed June 11, 1921.

The present invention relates generally to carburetors, and more particularly to an imroved construction of overflow drain. The invention has particular applicability to car- 6 buretors having inverted carbureting passageways in which the air intake is into the top of the carburetor and the mixture outlet is at the bottom. In such carburetors, even when in their normal positions, conditions are a tto arise which will tend to cause excess 0w of fuel from the nozzle into the carbureting chamber, and where such carburetors are used in airplanes where there is considerable tilting, there would also be a tendency for excess flow of fuel through the nozzle. Such excess fuel will run down in the intake manifold to the intake valves with the result that the cylinders are loaded or filled, and the crank case oil is diluted.

It is the important object of our invention to provide construction and arrangement for preventing excess fuel flow from the nozzle, or elsewhere, into the carburetiug passage, when the level of fuel in the float chamber is raised above the level of the nozzle outlet not only when the carburetor is in normal position, but during considerable tilting. positions thereof. This, we accomplish by pro viding an overflow or release passageway between the float chamber and the nozzle for intercepting any excess flow which would otherwise reach the nozzle and for discharging such excess in a safe manner without interfering with the proper eflicient mixture producing operation of the carburetor. While the invention has particular applicability to inverted carburetors, the utility of the invention is not limited thereto, but also extends to upright, inclined or horizontal carburetors, whether they may be applied to airplanes, motor cars, motorcycles, or to any other use. i

Referring to the accompanying drawing wherein we have illustrated in sectional view a carburetor embodying our invention, it will be observed that the casing 1 forms a vertical carbureting chamber 2 and in immediate proximity thereto forms a float chamber 3. The drawing illustrates an inverted type of aviation" carburetor having a flange/i for connection with a supercharger attachment, although it is to be understood that the pres Serial N0. 476,678.

a ring of packing 30 which is compressed by a beveled ring 40.- This packing is provided to form a leak-proof joint for preventing leakage of fuel from the drain space 20 down into the carbureting chamber. The lower end of the Venturi opens into the carbureting chamber and mixture outlet in which is disposed a throttle valve 9 operated through a suitable shaft 11. An idling nozzle 12 opens into this carbureting chamber in proximity to the throttle 9, this idling nozzle receiving fuel from the float chamber through aseries of passages, one of which is indicated at 13.

The upper edge of the Venturitube 7 is notched as indicated at 14 to receive a horizontal nozzle 15 which projects radially into the constricted throat of the Venturi tube. This fuel nozzle'has a plurality-of fuel discharge opening 16,- preferably emitting fuel downwardly therefrom, and the other end thereof is set into a horizontal stem 17 hav ing a fuel passage 18. The fuel passage 18 draws fuel from an accelerating and overflow well which is embodied in the casing or in the gasoline circuit at a point intermediate the float chamber 3 and the fuel nozzle 15. This well comprises a cylindrical enlargement 19 which projects into the intervening drain space 20 between the upper and lower walls 5 and 6. Projecting upwardly through the bore 21 of this cylindrical enlargement is a hollow stem 22 which feeds fuel to the fuel passage 18. The upper wall 5 has a circular opening 23 in alignment with thebore 21, the stem 18 having a flange 24 seating on the wall 5 around the periphery of this opening 23. A hub 25 spaced inwardly from the flange 24is threaded internally for the reception of the screw threaded end of the stem 22. A flange 26 on the stem 22 is adapted to bear against the internal flange 19 for drawing the flange 24 of the stem 17 down firmly around the opening 23. A dowel pin 27 or the like holds the stem 17 against lateral vibration. A flanged nut 28 screws over the lower end of the stem 22 and closes the bottom of the accelerating-overflow well, this nut having a central aperture 29 for admitting fuel to the bore 31 of the stem 22. The enlarged bore 32 for receiving this nut is closed at the bottom by a screw plug 33. A. diagonal fuel passage 34 supplies fuel to the bore 32 through a removable plug 35 having a restricted orifice 36. Fuel is admit ted from the float chamber 3 to the top of the plug 35 through an aperture 37, a removable plug 38 affording access to the restricted plug 35 for cleaning or substitution of the same.

The upper end of the accelerating and overflow well is completed by a sleeve ll which snugly fits at its lower end within the flange 19 and at its upper end extends up around the hub 25 in spaced relation thereto. ring 42 inserted in the opening 23 closes the joint between the flange 21 and the top of the wall 5 against leakage of fuel. The sleeve ell is also spaced from the ring 42 and terminates short of the stem 17 so as to pro vide a circular overflow opening 43. The normal fuel level is indicated by the dash and dot line az-a: and it will be noted that the top of the overflow opening 48 is above this level sufficiently far to prevent overflow of fuel eztcept upon relatively sharp inclinations of the carburetor. [it the same time the top of this overflow opening is sulliciently below the level of the fuel passage 18 to intercept overflow fuel before it reaches the fuel passage 18. This overflow opening also serves to admit atmosphere to the top of the acceleratin well for venting the same, as will hereinafter appear. The lower and upper parts 2l--21 of the well are connected by apertures ll in the flange 26, the spacing ring to having similar apertures for permitting the overflow discharge. The well 21-21 is adapted to re ceive and discharge its reserve accumulation of fuel through upper and lower series of ports l-ll and ll opening outwardly from the bore of the stem 22. The combined capacity these several ports tdl? is considerably in encess of that of the restricted orifice 36 in order to insure that the overflow outlet will be adequate to take care of all of the fuel discharged from the float chamber. The drain area 20 which is entirely closed from the rest" of the carburetor, extends around the ll'enturi tube 7' and has outlet connection through a boss 48 into which screws a drain pipe 49 leading outside of the fuselage or to any other point for the safe inaaava discharge of the fuel. In a duplex carburetor or a carburetor having a multiplicity of carbureting barrels the drain space 20 may be common to the accelerating wells of all of these carburet-ing barrels.

In the operation of the carburetor the supply of fuel for normal running is governed by the calibrated orifice 36, this fuel flowing up through the bore 31 of the stem 22 and out through the fuel nozzle 15 in an 0b vious manner. Upon acceleration the fuel in the well 2l21 is drawn into the bore 31 through the ports 46 and 47 to augment the normal supply flowing therethrough, and when the fuel level in the accelerating Well has dropped sufliciently far, air is bled 1nto the bore 31 from the substantially atmospheric pressure prevailing in the drain area 20. This accelerating well action is typical of the conventional vented accelerating well. Assume now that an overflow volume of fuel rises in the passage 31 and in the accelerating well 21 21. As soon as this fuel reaches the top of the sleeve 41 .it overflows through the opening t? into the chamber 20, and is thus diverted, from overflowing through the nozzle 15 and flooding the carburetor and engine. This overflow may result from various causes. If the float actuated needle in the fuel reservoir 3 should fail to seat properly, an overflow will occur. ll the float mechanism and needle valve should become jammed or temporarily inoperative from the sharp tilting or maneuvering of the air craft, this will cause an overflow. ll at an time the flow of fuel to the passage 31 an accelerating well should be in excess of that which the air entering the accelerating well is capable of picking up for discharge through the nozzle, this 81(- cess quantity will constitute an overflow, which will discharge over the top of the sleeve 11 in the majority of the angular o sitions that the carburetor may assume. he overflow fuel, of course, passes through one or more of the ports at and 4;? in discharging over the top of the sleeve ll. By reason of their greater capacity, these ports are al ways capable of permittin discharge of all the overflow fuel which tie restricted orilice 36 is capable of d'mcharging.

The typical air-bled accelerating well requires an inlet port for the admission of at mosphere, or of air under higher pressure than the suction prevailing in the carburetiug chamber, and it will lie noted that by combining and utilizing this inlet ort as an overflow drain a very simple an eflective arrangement is obtained. lln aviation practice it has heen proposed to control the proportion of the mixture by the regulation of the pressure in the float chamber, as has beeumade the subject matter of our copending application 321,199 filed A. ril 5, 1920, such control feature being preerably neeas'rs embodied in the present construction. closed float chamber is employed where this control feature is desired, and thus overflow from the top of the float chamber itself is prevented, The present arrangement of overflow drain has particular aptitude for use with this float chamber control by reason of the fact that the location of the overflow drain in the fuel circuit intermediate the float chamber and fuel nozzle affords an effective overflow outlet without interfering with the maintainanceof the proper pressure in the float chamber.

We claim:

1. In a carburetor, the combination of a carbureting chamber, a fuel nozzle opening into said chamber a float chamber supplying fuel to said fuel nozzle through a restricted passa eway, and an unrestricted fuel diverting pat permitting the raising of the fuel level in said float chamber above the level of said fuel nozzle without issuance of an overflow of fuel from said nozzle, said nozzle retaining communication with said float chamber during said variations in fuel level.

2. In an aeroplane carburetor, the combination of a carbureting chamber, a fuel nozzle opening into said chamber, a float chamber, a fuel passageway extending from said float chamber to said fuel nozzle, and unrestricted intercepting means cooperating with said fuel passageway for intercepting the abnormal flow of fuel to said fuel nozzle when the carburetor is inclined in certain positions.

' 3. In a carburetor, the combination of a carbureting chamber, a fuel inlet to said chamber, means for supplyin fuel to said fuel inlet comprising a fue passageway, an air bleed port opening into said fuel zle fed from said float chamber through a restricted orifice, a fuel overflow path'extending from the nozzle at a point below the normal fuel level therein and terminating above the normal fuel level, said path having less flow resistance than said restricted orifice whereby rise of fuel in said fuel chamber above normal fuel level will be prevented from flooding said nozzle.

6. In a carburetor, the combination of a carbureting chamber, a float chamber, a nozzle fed from said float chamber through a restricted orifice, a fuel overflow path extending from the nozzle below the normal fuel level therein and terminating outside of said carbureting chamber above the normal fuel level, said path being of less flow resistance than said restricted orifice whereby excess fuel flow into said nozzle from said float chamber will be diverted from the nozzle outlet and the carbureting chamber.

In witness whereof, we hereunto subscribe our names this 31st day of May, 1921.

FRANK C. MOGK. CHARLES J. GUSTAFSONA MILTON ECHANDLER. 

